Having adult ADD isn't a black and white kind of thing, there are many levels of adult ADD. Some people only have minor symptoms and don't need drugs, just therapy and a little counseling. Others have some or all of the major symptoms (misplacing things, trouble with numbers, hyperactivity or extreme laziness, wild mood swings, etc.) and do need to be medicated to deal with it. ADD is a chemical imbalance in the brain, but it's not a yes or no imbalance, there are degrees of it.
I do believe that many doctors are too eager to diagnose people with adult ADD today, some people may have some minor symptoms and it's just their personality that makes them seem that way, especially when they have no family history of ADD.